The present invention generally relates to methods, machines, and equipment for processing materials, for example, to reduce the size of, disperse, or homogenize a material.
Various types of equipment are known for processing materials, for example, slicing, dicing, shredding, granulating, comminuting, or otherwise reducing the size of solid materials. A widely used line of comminuting machines is commercially available from Urschel Laboratories, Inc., under the name Comitrol®, aspects of which are disclosed in patent documents including U.S. Pat. Nos. 4,660,778, 4,610,397, 4,657,190, and 5,201,469, whose contents are incorporated herein by reference. Comitrol® machines are capable of uniformly comminuting, dispersing, or homogenizing a wide variety of materials and compositions at high production capacities, for example, food products including fruits, vegetables, dairy products, and meat products, as well as nonfood products including polymeric materials, chemicals, and pharmaceuticals in a variety of forms (e.g., liquids, sols, gels, slurries, pastes, solids, etc.).
A known configuration for a Comitrol® machine is depicted in exploded views in FIGS. 1 and 2. The machine, the particular model of which is the Model 1700, is represented as comprising a cutting assembly 10 and feed hopper 12 through which material is fed to the cutting assembly 10 via a feed tube 13. FIGS. 1 and 2 depict the cutting assembly 10 as comprising an impeller 24 rotatably mounted within an annular-shaped cutting head 26. An electric motor 14 and drive belt 16 rotate a spindle 22 on which the impeller 24 is mounted for rotating the impeller 24 within the cutting head 26. Material delivered through the feed hopper 12 to the rotating impeller 24 is forced by paddles or blades 25 of the impeller 24 into engagement with uniformly spaced knives 40 mounted at the inner perimeter of the cutting head 26 and oriented parallel to the impeller axis. The spacings between the knives 40 affect the size of the resulting size-reduced product. An upper enclosure 18 surrounds the cutting assembly 10, from which size-reduced material exits and falls before being discharged from the machine through a lower enclosure 20. The particular cutting assembly 10 depicted in FIG. 1 is referred to as a “Microcut,” which is especially well suited for performing dispersion and homogenization processes to produce a variety of liquids, sols, gels, slurries, pastes, etc. As evident from FIG. 1, the depicted configuration is adapted to be mounted with a table that supports the motor 12.
FIGS. 2, 3 and 4 depict certain components of the machine of FIG. 1 in more detail. FIG. 2 depicts the impeller 24 separated from the cutting head 26 and a unit comprising a retaining ring, wear ring and face seal 28 through which the cutting head 26 is mounted within the machine. FIG. 3 is an exploded view showing certain components of the cutting head 26, namely, a backing ring assembly 34 that secures a pair of upper and lower knife holding rings 30 and 32 between and to, respectively, a pair of upper and lower support rings 36 and 38 that are spaced apart by posts 39. The backing ring assembly 34 comprises a pair of upper and lower retainer rings 35A and 35B spaced apart by posts 37, and the retainer rings 35A and 35B secure, respectively, the upper and lower knife holding rings 30 and 32 within recesses formed in the upper and lower support rings 36 and 38. FIG. 4 is a partial fragmentary view of the cutting head 26 showing the manner in which the knives 40 can be mounted and secured between the knife holding rings 30 and 32 to have a generally radial and axial orientation relative to the head 26 (and, therefore, to the impeller 24). Centrifugal force causes material delivered to the high speed rotating impeller 24 to move radially outward into engagement with the knives 40, where the material strikes exposed cutting edges of the knives 40. This action results in the removal of small particles from the material until reduction is completed. Particles are discharged through the gaps between the knives 40 before exiting the machine through the upper and lower enclosures 18 and 20.
Various other configurations of Comitrol® machines, including their drive systems, knife assemblies and impellers, are also available beyond that represented in FIG. 1. As a nonlimiting example, the cutting assembly 10 may comprise an impeller and cutting head that have smaller or larger axial and/or radial dimensions than what is shown in FIGS. 1 through 4, for example, including the configurations disclosed in U.S. Pat. Nos. 4,660,778, 4,610,397, 4,657,190.
Material reduction machines of the type described above and represented in FIGS. 1 through 4 have performed extremely well for use with a wide variety of materials and applications. For some applications, when dispersing a solid material in a liquid, the solid material and liquid may be delivered to the cutting assembly 10 together via the hopper 12, for example, combined to form a mixture prior to entering the hopper 12, or combined within the hopper 12 to form a mixture. In such cases, it may be desirable or necessary to control the relative amounts of solid material and liquid delivered to the cutting assembly 10, for example, to obtain a mixture having a desired consistency, viscosity, etc., for processing by the assembly 10. In addition or alternatively, it may be desirable or necessary to separately deliver additional liquid to the assembly 10 apart from the solid material or mixture. One such example is the dispersion and dissolving of solid materials in a liquid to produce a sol, gel, slurry, paste, etc., a particular example of which is the production of polymer-water suspensions used to displace oil in enhanced oil recovery (EOR) and oil sands tailings treatment applications. To produce such suspensions, a mixture of water and solid particles of a water-soluble polymeric material can be introduced into a Comitrol® machine, where the polymer particles are comminuted and then dissolved in the water. In such applications, there are occasions where the final suspension exhibits more desirable properties for its intended use if it contains more water than what may be needed or optimal for cutting and dissolving the polymer particles. Alternatively or in addition, it can be advantageous to rinse the knives of the cutting head during operation to avoid a build-up of comminuted polymer particles between the knives. In either case, Comitrol® machines have been modified with nozzles fed by external water lines or manifolds to direct high pressure water at the outer perimeter of their cutting heads.